In the story, Cersei Lannister, Queen of the Seven Kingdoms of Westeros, is the wife of King Robert Baratheon. Her father arranged the marriage after his attempt to betroth her to Prince Rhaegar Targaryen, as she wanted, failed. The Targaryen dynasty lost the war, and her father schemed his way into the role of a political counselor for the newly crowned King Robert. The Lannisters are the richest family in Westeros and helped him to win the Throne, which is why Robert agreed to a marriage between them. Cersei has a twin brother, Jaime, with whom she has been involved in an incestuous affair. All three of Cersei's children are Jaime's, which is unbeknownst to the king and causes a power struggle in the wake of his death known as the 'War of Five Kings'. Cersei's main character attributes are her lust for power and love for her children, whom she seeks to protect.

Cersei is the only daughter and the eldest child of Tywin Lannister and his wife, Joanna; her twin brother, Jaime, was born soon after Cersei. Cersei and Jaime looked so similar as children that Cersei occasionally wore Jaime's clothes and was mistaken for him.[1]

The twins experimented sexually at an early age but were discovered by a servant, who informed their mother. Joanna tasked a guard to keep the twins separated and kept the matter a secret from their father, threatening the twins that she would inform him if they ever repeated it.[2]

Soon afterward, Joanna died giving birth to the twins' younger dwarf brother, Tyrion. Cersei blamed Tyrion for Joanna's death and started to abuse him as a baby.[2] Martin said in Rolling Stone:

There's certainly a great level of narcissism in Cersei. She has an almost sociopathic view of the world and civilization.[3]

From the time she was very young, Tywin hoped his daughter would marry Rhaegar Targaryen, and he rejected the Princess of Dorne's proposal to betroth Oberyn Martell and Elia Martell to Cersei and Jaime, respectively. Cersei became infatuated with Rhaegar; feelings she hid from her brother as her father advised her.[4]

At the age of 11, Jaime was sent away to serve as a squire for Lord Sumner Crakehall.[2] A year later, Aerys Targaryen rejected the proposal that Cersei marry his son, humiliating Tywin.[4] Tywin took Cersei to King's Landing and, in the following years, refused every offer of marriage for her. In 281 AC, when Cersei and Jaime were 15, Jaime, newly knighted on the battlefield and on his way to Casterly Rock, came to King's Landing to visit his sister, from whom he had been separated for four years. She informed Jaime that their father planned to marry him to Lysa Tully and persuaded him to join the Kingsguard in order to be near her, after the twins had slept together for the first time.[2] Thus started an affair that continued throughout Cersei's marriage to Robert Baratheon.

While she was initially happy about marrying Robert,[5] he didn't return Cersei's affections and repeatedly cheated on her. She then resumed her incestuous affair with Jaime, resulting in the births of Joffrey, Myrcella, and Tommen.

During her teenage years, believing that her betrothal to Rhaegar would soon be announced, Cersei brought her companions Melara Hetherspoon and Jeyne Farman to a witch named Maggy the Frog. Jeyne was instantly frightened and left the tent. Cersei and Melara stayed and tried to get the witch to tell them a prophecy. In the face of Cersei's threats, Maggy agreed to answer three questions. In response to those questions, Maggy told Cersei she would marry the king and not the prince, that she would be overthrown by a younger and more beautiful queen, that Cersei's children would die during Cersei's lifetime, and that the valonqar (High Valyrian for "little brother") would come to end her life.

Melara then asked if she would marry Jaime; Maggy answered that Melara wouldn't marry anyone and would die that night. It is implied that Cersei killed the girl to prevent her from speaking of the prophecies and for having ideas above her social status.[4] Cersei spends her entire adult life attempting to subvert the prophecy and develops a strong paranoia, which eventually causes the prophecy to come to fruition.

Robert, Cersei, and most of the court visit the North to appoint Eddard Stark as Hand of the King. During the royal visit to Winterfell, Eddard's son Bran finds Cersei and Jaime committing incest in a tower. To prevent their adultery and incest from being revealed, Jaime pushes Bran from the tower. Bran survives, but has no memory of the fall and is left paraplegic.

Eddard eventually discovers the truth of Cersei's infidelity and confronts her, giving her the opportunity to flee into exile and thus spare her children certain execution. Cersei had already arranged Robert's death in a hunting "accident"; when he dies, Cersei seizes control as regent and has Eddard arrested for treason. Cersei intends for Eddard to publicly confess and join the Night's Watch as punishment, but instead Joffrey orders Ned executed.

Frustrated with Cersei's many political blunders as well as her failure to control Joffrey, Tywin appoints Tyrion Hand of the King, with explicit instructions to control Cersei and Joffrey. Once at the capital, Tyrion enters into a bitter power struggle with Cersei, subverting her authority and removing her supporters from positions of power.

In Jaime's absence, Cersei takes their cousin Lancel Lannister as her lover, an affair that Tyrion discovers. When Stannis Baratheon sails on King's Landing, Cersei and Joffrey stay enclosed in the Red Keep, leaving Tyrion to mastermind the defense of the city. Ultimately, Tywin and the Tyrell armies arrive in time to force Stannis to retreat and save the city.

After formally assuming his position as Hand of the King, Tywin makes it clear to Cersei that she is no longer welcome at the small council meetings, de facto stripping her of political authority. Furthermore, Tywin intends to wed Cersei to Wilas Tyrell in order to form an alliance with House Tyrell. This state of affairs is shaken when Joffrey is poisoned at his wedding feast. Maddened with grief at the loss of her eldest child, Cersei lashes out against Tyrion, accusing him of poisoning the king out of revenge.

Cersei manipulates Tyrion's trial to ensure a guilty verdict, by bribing and intimidating witnesses. When Tyrion demands a trial by combat, Cersei selects the imposing Gregor Clegane, "The Mountain," as the Crown's champion. The Mountain prevails, killing Tyrion's champion Oberyn Martell. Tywin then pronounces Tyrion guilty and sentences him to death, but Tyrion escapes prison and kills Tywin. Cersei is once again in complete control of the capital.

With the deaths of her father and elder son, Cersei's youngest child, the 8-year-old Tommen Baratheon, is crowned king, and Cersei rules the Seven Kingdoms as Queen Regent. Cersei's rule descends into a series of political and economic blunders due to her short temper, egotism, and paranoia, greatly damaging her relationship with Jaime and alienating allies such as Pycelle and Kevan Lannister. She defaults on debts to the Iron Bank of Braavos and to the Faith, allowing the latter to rebuild its military orders in exchange for cancellation of the debt, and fills government posts with ineffective and untrustworthy cronies and sycophants. At the same time, the Tyrells begin to build power in the capital, much to Cersei's consternation.

Cersei is haunted by the prophecy of the valonqar, whom she considers Tyrion, so she promises a lordship to whomever brings her Tyrion's head. This, however, only leads to many wrongful executions throughout the realm. In an attempt to undermine the Tyrells, and release her son from his marriage to Margaery Tyrell, Cersei attempts to frame Margaery for adultery and treason. However, this plot backfires as the investigation into Margaery reveals evidence of Cersei's own adultery and her complicity in Robert's death, resulting in her arrest by the Faith. Cersei sends a letter to Jaime, asking him for help, but he ignores her request and burns her letter.

To gain release from her imprisonment, Cersei confesses to several of the lesser charges against her, including post-marital affairs, but does not confess to having murdered her husband King Robert, nor that her children are the product of incest. Cersei is nevertheless punished with a walk of atonement, forcing her to strip and walk naked through the capital in full view of the public.

With Cersei confined to the Red Keep awaiting trial, the realm is governed by Pycelle and Kevan. However, at the nadir of Cersei's fortunes, Varys reappears at the capital and assassinates both Pycelle and Kevan, as their competent leadership threatened to undo the damage Cersei's misrule had done.

Cersei Lannister is played by Lena Headey in the television adaption of the book series.

In October 2014, Headey and several other key cast members, all contracted for six seasons of the series, renegotiated their deals to include a potential seventh season and salary increases for seasons 5, 6, and 7.[6][7]The Hollywood Reporter called the raises "huge", noting that the deal would make the performers "among the highest-paid actors on cable TV".[6]Deadline Hollywood put the number for season 5 at "close to $300,000 an episode" for each actor,[7] and The Hollywood Reporter wrote in June 2016 that the performers would each be paid "upward of $500,000 per episode" for season 7 and the potential season 8.[8] In 2017, Headey became one of the highest paid actors on television and will earn £2 million per episode for the show.[9][10]

Much of Cersei's storyline from the first and second seasons in the television series is unchanged from the books. However, a notable change in the show is Joffrey's authorising the purge of Robert's bastards, rather than Cersei.

Cersei learns that her husband Robert is in danger of finding out that the children he sees as his heirs to the throne are not his.[11] Robert meets his end as the result of a boar attack on a hunting trip, before Ned Stark tells him the truth about his children. Cersei works quickly to instate her oldest son, Joffrey, on the throne, with her as his chief political advisor and Queen Regent.[12] Joffrey, however, quickly shows signs of independence.

Tywin decides that Cersei does not exercise enough control over her son and sends Tyrion as an additional political advisor. Cersei and Tyrion do not get along, and constantly try to undermine each other's authority over the crown. As of the end of season 2, Tyrion has accumulated more sway over the Iron Throne, has shipped Cersei's only daughter off against Cersei's will to be married to the Prince of Dorne, and is forcing their cousin Lancel, with whom Cersei is having an affair, to inform on her. Tywin's arrival with the Tyrell army robs both siblings of their influence at the last possible moment.

Cersei comes to fear that Margaery Tyrell intends to usurp her as queen and unsuccessfully tries to alienate Joffrey from her. Cersei is delighted when Tywin learns of the Tyrells' plan to wed Sansa Stark to Margaery's brother Loras, and he intervenes by having Tyrion marry Sansa instead, but is furious when Tywin also orders Cersei to marry Loras. When Jaime returns to King's Landing, he immediately seeks out Cersei, who is shocked to discover that his sword hand has been cut off.

Cersei has Tyrion arrested after Joffrey is fatally poisoned. Mourning and vindictive, it's implied that guilty or innocent, she wants Tyrion dead, while Jaime refuses to believe Tyrion is capable of familial regicide.[13] Indeed, at Tyrion's trial, it is apparent Cersei has manipulated the proceedings so that the witnesses give either incomplete or entirely false testimonies to implicate Tyrion and Sansa further in the murder. When Tyrion demands a trial by combat, Cersei chooses Ser Gregor "The Mountain" Clegane as royal champion, to further diminish Tyrion's chances, and bribes Bronn via betrothal to a noblewoman, to secure his veto as Tyrion's champion. Cersei's wish comes true when Tyrion's champion, Oberyn Martell, is killed by Clegane. She still refuses to marry Loras, threatening even to reveal the truth of her incestuous relationship with Jaime and their three blond children. Tywin is killed by an escaping Tyrion soon afterward.

Cersei receives a threat from Dorne, where Myrcella is betrothed to Trystane Martell, and sends Jaime to Dorne to retrieve her. Tommen is married to Margaery, who tries to manipulate Tommen into sending Cersei to Casterly Rock. Fearful of losing her power, Cersei meets the religious leader, the High Sparrow, appoints him as the High Septon, and gives him authority to re-establish the Faith Militant. In order to destabilise House Tyrell, Cersei arranges for the High Sparrow to arrest Loras for his homosexuality, and have Margaery also arrested for perjury after lying to defend Loras. However, Cersei's plot backfires when Lancel, now a member of the Faith Militant, confesses to his affair with Cersei and his role in Robert's assassination, and accuses Cersei of incest, prompting the High Sparrow to arrest her. Cersei is eventually allowed to return to the Red Keep after confessing to having committed adultery with Lancel, but has her hair cut off and is forced to walk naked through the streets of King's Landing as atonement. Cersei returns, distraught from the abuse directed at her by the smallfolk of King's Landing, but is consoled by Qyburn's successful reanimation of Ser Gregor Clegane.[14]

Cersei remains in the Red Keep, confined to her chambers and stripped of her authority. Although she accepts Tommen's apology for his lack of action in her arrest and walk of atonement, she remains looked down upon by other members of the court. Cersei learns from Tommen that the High Sparrow plans to have Margaery do a walk of atonement before Cersei's trial and conspires with the Small Council to have the Tyrell army march on the Sept of Baelor to secure Margaery's and Loras' release. Their plan backfires when it is revealed that Margaery has joined the Faith of the Seven and has convinced Tommen to merge the Faith and the Crown. Despite being stripped of her allies, Cersei opts to remain in King's Landing, having named Ser Gregor as her champion in her trial by combat. However, Tommen announces that trial by combat has been abolished and replaced by trial by the Seven. Cersei arranges for a cache of wildfire to be detonated beneath the Sept during Loras' trial, which kills the High Sparrow, Margaery, Loras, and the rest of the Small Council. As a result of Cersei's actions, Tommen commits suicide. In the power vacuum following Tommen's death, Cersei claims the Iron Throne as the first ever Queen Regnant of the Seven Kingdoms.[15]

Despite nominally being ruler of Westeros, Cersei's grip on the throne is tenuous, with the Riverlands in upheaval following Arya Stark's massacre of House Frey, the Vale and the North's declaration of Ned Stark's bastard son Jon Snow King in the North, and Tyrion, Yara Greyjoy, Dorne, and the Reach all supporting Daenerys Targaryen, whose fleet has seized Dragonstone. Cersei remains cold and distant after Tommen's suicide, viewing it as a betrayal of their family. With no children left to protect, Cersei's malice and vindictiveness have grown, and she relentlessly seeks to expand her power and destroy her enemies. Cersei reaches out to the King of the Iron Islands, Euron Greyjoy, to form an alliance, but rejects Euron's marriage proposal as she considers him untrustworthy. Euron later ambushes Daenerys' fleet and captures Yara Greyjoy, Ellaria, and Tyene Sand, and presents them as a "gift" to Cersei. She agrees to marry Euron after the war is won; however, she continues her affair with Jaime, no longer attempting to hide their relationship from their servants. Cersei imprisons Ellaria and Tyene in the dungeons, kills Tyene with the same poison used to kill Myrcella, and keeps Ellaria alive to watch her daughter die.

Tycho Nestoris of the Iron Bank arrives in King's Landing to request repayment of their debt. Cersei requests a fortnight in order to comply. She then has the Lannister and Tarly armies attack Highgarden, defeating the Tyrells. Olenna Tyrell commits suicide following the defeat and gloats to Jaime that she was responsible for poisoning Joffrey. The Tyrells' wealth is transported safely to King's Landing, but the food the Lannisters steal from the Reach is destroyed when Daenerys attacks the caravan with her Dothraki horde and dragon, Drogon. Jaime barely survives the battle and encourages Cersei to consider a ceasefire.

Tyrion infiltrates the capital to meet with Jaime, and Jaime tells Cersei that Daenerys and Jon want to meet with Cersei to negotiate an armistice while mankind fights the threat of the White Walkers. Cersei is skeptical but agrees, and tells Jaime that she is pregnant. Daenerys and Jon meet with Cersei in the Dragonpit on the outskirts of King's Landing, and present to her a wight captured from the White Walkers as evidence of their threat. Although terrified, Cersei initially refuses to agree to an armistice, as Jon refuses to remain neutral in the war between the Lannisters and Targaryens. Tyrion speaks to Cersei in private, and apparently persuades her to ally with the rival monarchs. However, she later reveals to Jaime that she intends for her enemies to wipe each other out and then attack the victor, and has sent Euron to Essos to transport the Golden Company to Westeros. Disgusted by Cersei's selfishness and shortsightedness, Jaime finally abandons her side and goes north on his own, leaving Cersei alone.

Cersei is informed that the White Walkers have breached the Wall, to her delight. Euron Greyjoy returns to King's Landing with the Golden Company, and Cersei finally has sex with him. Cersei tasks Qyburn with hiring Bronn to kill Jaime and Tyrion, using the crossbow with which Tyrion had killed Tywin.

Cersei permits civilians to seek refuge in the Red Keep – ostensibly to protect them from an invasion of King's Landing, but in reality she plans to use them as human shields to deter an attack. The Iron Fleet kills one of Daenerys' dragons, Rhaegal, and takes her advisor Missandei captive. When Euron returns to King's Landing, Cersei reveals that she is pregnant and lies that it is his. Daenerys, Tyrion, and her other advisors travel to King's Landing demanding Cersei's surrender, but Cersei is unmoved and has the Mountain behead Missandei in front of Daenerys. Daenerys subsequently launches an attack on the Iron Fleet, the Red Keep, and the anti-dragon defenses Cersei has had installed on King's Landing's walls, but then continues to burn the rest of the city. Cersei attempts to take shelter and is found by Jaime, who had infiltrated the Red Keep on Tyrion's orders to evacuate her. However, their passage is blocked by rubble. The Red Keep begins to collapse, and Jaime comforts Cersei in their final moments as they are crushed by falling debris. Their bodies are later found by Tyrion, whose subsequent grief leads him to renounce his loyalty to Daenerys and persuade Jon Snow to kill her.

In 2019, Lena Headey and Peter Dinklage appeared as Cersei and Tyrion Lannister alongside Elmo in a Sesame StreetPSA on the importance of being respectful to one another, as part of Sesame Street's "Respect Brings Us Together" campaign.[16]

Cersei has been continuously praised as one of the most complex and multi-faceted characters in either version of the story. Rolling Stone ranked her at No.5 on a list of the "Top 40 Game of Thrones Characters", describing Cersei as a character who'd "rather die than give you control".[17] On a similar list made by Rolling Stone ranking the "30 Best Game of Thrones Villains", Cersei was ranked No.1 and described as the "most dangerous human being in Westeros" as well as "one of the most complex and fascinating characters on television.....she's also a strangely sympathetic figure, warped by being treated like an expensive brood mare by powerful men her entire life and genuine in her affections".[18] Alyssa Rosenburg of The Washington Post wrote, "As the men....destroy themselves and each other, leaving a generation of women without husbands, sons, and marriage partners, [Cersei] may be the only [person] left to repair the shattered world".[19] James Hibberd of Entertainment Weekly wrote glowingly of Headey's Cersei: "Many members of the show's cast have improved over the years, but Headey has been winning raves from critics from the very start — since the early episodes of season 1 Headey has perfectly delivered Cersei’s uniquely toxic mix of pride, vindictiveness, impatience, cunning, and spite. Given Cersei’s long list of murderous sins, the character by all rights should be considered GoT’s outright villain. Yet thanks to the show’s textured writing and Headey’s delivery, Cersei has never been anything less than a fully realized character."[20]

Lena Headey has received much critical praise and acclaim for her portrayal of Cersei,[21] and has received multiple accolades including the Portal Award for Best Actress in 2012,[22] the EWwy Award for Best Supporting Actress in a Drama in 2012,[23] the Women's Image Network Award for Actress Drama Series in 2014,[24] and the Gold Derby TV Award for Best Drama Supporting Actress in 2015 and 2016.[25][26] Andrew Anthony in The Guardian opined that Game of Thrones was "most often at its best when Headey was on screen and radiating cold calculation and ruthless intrigue." He described Headey's Cersei as "a study in tyranny as a seductive art. There was something magnetically human about her inhumanity. You were drawn to her devious charms even as you recoiled from her brutal deeds."[27]